Encased propellant for a rocket motor



Dec.- 30, 1969 a R EDMAN ETAL ENCASED PROPELLANT FOR A ROCKET MOTOR Original Filed Jan. 10, 1967 1 N VEN TORS BJORN @0001. F EDMAN 0L OF OMAN Y MMEQW US. Cl. 6039.47

United States Patent 3,486,330 EN'CASED PROPELLANT FOR A ROCKET MOTOR Bjorn Rudolf Edman, Karlskoga, and Olof Oman, Valasen, Sweden, assignors to Aktiebolaget Bofors, Bofors, Sweden Original application Jan. 10, 1967, Ser. No. 608,358. Divided and this application May 1, 1968, Ser. No. 725,716

Claims priority, application Sweden, Jan. 21, 1966,

Int. Cl. F02k 9/04 3 Claims ABSTRACT OF THE DISCLOSURE A body of a solid propellant encased in a tubular container to eifect burning of the propellant from one of the ends of the propellant rather than along the entire wall surface of the propellant.

The present application is a divisional application divided out of our copending application Ser. No. 608,358 filed Jan. 10, 1967.

The invention relates to a solid mass composed of granular particles and a hardened initially liquid binder and encased in a tubular container, and more particularly, the invention relates to a rocket motor propellant in the form of a solid body composed of granular particles such as nitrocellulose powder and an initially liquid gelatinization agent such as nitroglycerine and encased in a generally cylindrical container to effect burning of the propellant from one end only rather than along the wall of the propellant.

It is a broad object of the invention to provide a novel and improved encased propellant mixture in the form of a solid body which when ignited will burn from one end only, preferably the top end, rather than along its side wall, and which can be safely, economically and rapidly manufactured.

Other objects, features and advantages of the invention will be set forth in the appended claims constituting part of the application.

In the accompanying drawing, a preferred embodiment of a container filled with a propellant in the form of a solid body and the manner of filling the container with the propellant mixture are shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is an elevational perspective view, partly in section, showing a container filled with propellant powder and a device for injecting a gelatinization agent into the container, said device being shown inactive;

FIG. 2 is a perspective view similar to FIG. 1, but showing the injection device in operation; and

FIG. 3 is a view similar to FIGS. 1 and 2, but showing the injection device withdrawn from the container after completion of the operation.

Referring now to the figures more in detail, there is shown a container in the form of a cylindrical tube 1 having at one end, in practice the lower end, an inwardly directed peripheral flange 2, the other end being open. The tube and its flange are preferably integral but in any event preferably made of the same material such as cellulose acetate. The purpose of the tube is to prevent buming of the propellant material along its cylindrical surface and also to serve as heat insulation to protect a motor which may be located adjacent to the propellant.

The center opening defined by flange 2 is covered with an elastic disk 3 made of a self-sealing material such as rubber, and secured to the flange, preferably to the outside thereof, by a suitable and conventional adhesive. The tube is filled through its open upper end by means of a con- Patented Dec. 30, 1969 ventional metering device with a suitable propellant powder 4 such as nitrocellulose powder plus additives as may be required in propellant powders. After filling the tube with powder to the desired level, a disk 5 having apertures 6 is placed in the tube to hold the nitrocellulose powder filling in position.

The filled tube, now closed off at both ends, is placed, preferably in upright position, above the injecting device. This device is shown as comprising an. injection needle 7 having a pointed end 9 and an outlet aperture 8 below the point 9. The other end of the needle is extended into a hollow head which, via a pipe stub 11, communicates with a hose 12. This hose should be visualized as being connected to a pressurized supply of a hardening gelatinization agent such as nitroglycerine, or other nitrate esters with or without desensitizing agents. Head 10 is mounted on one end of a rod 13, the other end of which mounts a piston 14 slidable in a cylinder 15. The cylinder communicates at opposite ends with conduits 16 and 17 for feeding a pressurized gaseous or liquid fluid into the cylinder and discharging the same therefrom.

As shown in FIG. 2, feeding pressurized fluid into the cylinder through conduit 16 will cause the piston to be lifted in the cylinder, fluid in the space above the pist n being discharged through conduit 17. As a result, needle 7 will pierce disk 3 so that the discharge aperture 8 is now located within the enclosed space of the tube filled with powder. The liquid gelatinizing agent is now fed through hose 12 and head 10 into the tube, thereby gradually filling the interstices between the powder particles in the tube. After the powder has been sufliciently saturated, which manifests itself by liquid percolating through apertures 6, the feed of the liquid agent is discontinued.

Upon completion of the filling of the tube with the gelatinization agent, the needle of the injection device is lowered by feeding pressure fluid through conduit 17 and discharging fluid through conduit 16, as is indicated in FIG. 3. Upon withdrawal of the needle, the puncture made in the disk by the needle will automatically close itself.

When the gelatinization agent has fully hardened the mixture in the tube becomes a solid body completely filling the same to the extent determined by the level of cover disk 5. No further operation is necessary either at the bottom end or the top end of the tube. In other words, the encased propellant is now ready for installation in a rocket motor.

While the invention is particularly suitable in connection with rocket motors requiring burning of the propellant from one end only, the invention can be advantageously used wherever it is necessary to fill a container with a powderized material which is then to be transformed into a solid body by adding a hardening binder thereto.

What is claimed is:

1. A rocket motor fuel element comprising in combination:

a tubular member made of plastic, said member being open on one end and having an inwardly turned peripheral flange on the other end, said flanged end constituting the bottom end of the fuel element;

a disk made of an elastic self-sealing sheet material adhered to said flange and covering the opening defined by said flange;

a solid rocket motor propellant composed of a mixture of a granular material and a hardened liquid filling said tubular member; and

a perforated cover plate covering said propellant at the open end of the tubular member.

2. The fuel element according to claim 1 wherein said granular material is granulated nitrocellulose powder and said hardened liquid is hardened nitroglycerine.

' 3 4 3. The fuel element according to claim 1 wherein said 3,202,730 8/1965 Gordon et al. 264-3 disk is adhered to the outside of said flange overlapping 3,205,286 9/1965 Black 86-1 XR the same. 3,222,433 12/ 1965 Makay 264-3 References Cited UNITED STATES PATENTS 5 CARLTON R. CROYLE, Primary Examiner U.S. Cl. X.R. 

